Membrane‐based therapeutic plasma exchange: Hemodynamics and operational characteristics leading to procedure failure

Abstract

Background and Objectives: Therapeutic plasma exchange (TPE) is a blood purification treatment capable of removing large molecular weight substances from plasma. It is commonly used for the removal of circulating pathogenic immunoglobulins presumed to be the cause of many autoimmune diseases. TPE can be performed with a membrane-based system (mTPE) or a centrifugal-based system (cTPE). When plasma separation is performed with a membrane, filter clotting can lead to longer treatment time, higher cost and can negatively impact patient satisfaction. In this study, we examine the operational characteristics that might influence filter life. Design, Setting, Participants, & Measures: We report on 24 patients, with a total of 135 mTPE treatments in a single tertiary care academic center using the NxStage machine. The study focuses on treatment specific parameters that may lead to procedure failure. The main parameters of interest were transmembrane pressure (TMP) and the filtration fraction as displayed on the machine (FFd) compared to the calculated filtration fraction (FFc). Primary outcome was to measure whether TMP, FFc, and FFd influenced filter survival. Secondary outcomes included factors that might have indirectly resulted in filter failure, including hematocrit (Hct), platelet count, heparin use, and intra-treatment calcium administration.Results: In this study, we demonstrated that machine displayed filtration frac-

Impact of prefilter dilution on IgG removal in membrane‐based therapeutic plasma exchange

“…In patients that received both prefilter heparin and saline solution, we observed a filter failure rate of 5.2%. This is in comparison to our prior experience where we noted 17.7% filter failure during which 80% of treatments used prefilter heparin (either bolus or infusion) without the use of prefilter saline infusion [7]. A previous study by Gashti et al reported a filter failure of 7.7% in 998 treatment sessions of which only 3.4% received some form of intratreatment anticoagulation [13].…”

“…Currently, with pump driven continuous veno‐venous hemofiltration, the predilution mode remains useful as a means of decreasing the tendency for filter clotting [6]. Given the proven benefits of predilution during CRRT, and the high rate of filter failure previously encountered (17.7%) [7], we initiated a protocol for predilution during mTPE in an attempt to reduce the risk of filter failure.…”

Membrane‐based therapeutic plasma exchange: Proposed techniques for preventing filter failure

“…Prior studies have demonstrated a therapeutic plasma exchange filter failure rate (FFR) ranging from 7.7% to 17.7%. 10,11 As we previously demonstrated, pre-filter normal saline administration does not affect the efficiency of IgG removal. 9 The purpose of this study was to examine the effect of pre-filter heparin and saline on the FFR.…”

“…Calcium supplementation was only used in early treatment cases when using 5% albumin replacement solution as we observed a tendency toward filter failure in subgroup analysis when using higher calcium doses without a significant change in post-treatment ionized calcium levels. 11 It was postulated that at physiological steady state 45%-55% of calcium is bound to albumin in the blood, yet an earlier study by Hester et al, demonstrated that by using 5% albumin solution that fraction can increase up to 86%-90%. 12 It was also described that calcium ionization is inversely proportional to pH, and at pH of 6.5 up to 80% of ionized calcium is available, which can decrease to around 40% at a pH of 8.0.…”

Anti-Interferon Autoantibodies in Adult-Onset Immunodeficiency Syndrome and Severe COVID-19 Infection

“…Therapeutic plasma exchange is a plasma purification treatment capable of eliminating large molecular weight substances from blood ( 101 ). It is the fastest way to remove circulating autoantibodies.…”